It may be true that in strict law, and from the standpoint of positive law, the promise may be obligatory only and capable of enforcement when it has been accepted, and accepted in an obvious and open way; but in natural law and in morality, the promise is obligatory in itself. Of course, it is understood that the promise bears on something advantageous to him to whom we make it; for if I promise some one a thrashing, it cannot be maintained that I am obliged to give it to him; and if he to whom I make the promise will not receive what I offer, I am by that very fact relieved from my promise; for one cannot give anything to another against his will; I am under no obligation to him who will not receive anything from me. But if the promise bears on something advantageous to any one, I am obliged to keep it without asking myself whether he to whom I made it, is disposed to accept it; presuming still that he will accept it. It is therefore not the explicit acceptance of a thing that renders the promise obligatory; it is the explicit refusal which relieves one of the promise; and together with that it would be necessary that the refusal be absolute and not contingent; for even then the promise may remain obligatory, at least in its general principles, while undergoing some modification in the execution. Is one obliged to keep his promise when the fulfillment of it is injurious to those to whom it was made? "No," says Cicero; for example: Sol had promised Phaethon, his son, to fulfil all his wishes. Phaethon wished to get on the chariot of his father; he got his wish, but at the same instant he was struck with lightning. It would have been better for him had his father not kept his promise. May we not say the same of the one Theseus claimed of Neptune? This god having made him the promise to grant him three wishes, Theseus wished for the death of his son Hippolytus, whom he suspected of criminal love.[34] How bitter the tears he shed when his wish was accomplished! What shall we say of Agamemnon? He had made a vow to immolate the most beautiful object in his kingdom; this was Iphigenia; and he immolated her; this cruel action was worse than perjury. The truth of this doctrine cannot be contested. However, it is necessary to understand this exception in the strictest sense, and not to seek in the pretended interest of the person one obliges, a pretext to change one's mind. For example, if you have promised any one a post which he accepts and desires, you cannot be allowed to relieve yourself of it, by supposing that the post will in reality be a disadvantage to him, and that you will give him a better one another time. Some other exceptions are pointed out by the moralists and jurists; for example: 1. Necessity relieves of all promise. If, for example, I have promised to go to a meeting and am kept in bed by a serious illness, it is impossible for me to go, and hence I am relieved of my promise.